Organic Arrows

Your arrows are smooth & you've compressed these as they go further away from viewer so they can flow through 3d space nicely. In most of the arrows I see a lot of time that you've applied lineweight in places they were not needed like the arrows head & tail, keep them just to where they're needed(on the curves).

Leaves

Your leaves are drawn confidently & follows the flow line most of the time. You should try doing more folded leaves in your future warm ups as I didn't see much variety here. Use references if you can.

Branches

Ellipses in these brances are perpendicular to the flow line & changing their degrees gradually, nice work. Edges of these branches are leaving visible tails, it's natural at first but with more ghosting & practice you can improve on having them overlap with adjacent edges nicely.

Plants

These palnts drawing are drawn as instructed for most part. You've kept the parts of plants enclosed in it's planned ellipse.

In Hibiscus, I see that on some petals you've different pattern of contour lines, keep them uniform among the petals if you can.

In Sunflower, you seem to be drawing the petals without observing the reference enough. It's better to have few petals(if the reference seems busy & confusing), each with planned flow & care. If possible try to do them again when you get time.

You've done great job on the shadow casting around the forms. If you've shaded only the shadows in maple leaves then good job they're good & you've a great eye. I personally have a tough time noticing them.

Overall, other than these little nitpicks your constructions are good.